using System;
using System.Collections.Concurrent;
using Microsoft.Extensions.Configuration;
using StackExchange.Redis;

namespace RedisHelper
{
    /// <summary>
    /// ConnectionMultiplexer对象管理帮助类
    /// </summary>
    public static class RedisConnectionHelp {
        //系统自定义Key前缀
        public static readonly string SysCustomKey = ConfigurtaionHelper.Instance.GetConfiguration () ["WebConfig:Redis:Key"] ?? "";

        private static readonly string RedisConnectionString = ConfigurtaionHelper.Instance.GetConfiguration () ["WebConfig:Redis:Connection"] ?? "";

        private static readonly object Locker = new object ();
        private static ConnectionMultiplexer _instance;
        private static readonly ConcurrentDictionary<string, ConnectionMultiplexer> ConnectionCache = new ConcurrentDictionary<string, ConnectionMultiplexer> ();

        /// <summary>
        /// 单例获取
        /// </summary>
        public static ConnectionMultiplexer Instance {
            get {
                if (_instance == null) {
                    lock (Locker) {
                        if (_instance == null || !_instance.IsConnected) {
                            _instance = GetManager ();
                        }
                    }
                }
                return _instance;
            }
        }

        /// <summary>
        /// 缓存获取
        /// </summary>
        /// <param name="connectionString"></param>
        /// <returns></returns>
        public static ConnectionMultiplexer GetConnectionMultiplexer (string connectionString) {
            if (!ConnectionCache.ContainsKey (connectionString)) {
                ConnectionCache[connectionString] = GetManager (connectionString);
            }
            return ConnectionCache[connectionString];
        }

        private static ConnectionMultiplexer GetManager (string connectionString = null) {
            connectionString = connectionString ?? RedisConnectionString;
            var connect = ConnectionMultiplexer.Connect (connectionString);

            //注册如下事件
            connect.ConnectionFailed += MuxerConnectionFailed;
            connect.ConnectionRestored += MuxerConnectionRestored;
            connect.ErrorMessage += MuxerErrorMessage;
            connect.ConfigurationChanged += MuxerConfigurationChanged;
            connect.HashSlotMoved += MuxerHashSlotMoved;
            connect.InternalError += MuxerInternalError;

            return connect;
        }

        #region 事件

        /// <summary>
        /// 配置更改时
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerConfigurationChanged (object sender, EndPointEventArgs e) {
            Console.WriteLine ("Configuration changed: " + e.EndPoint);
        }

        /// <summary>
        /// 发生错误时
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerErrorMessage (object sender, RedisErrorEventArgs e) {
            Console.WriteLine ("ErrorMessage: " + e.Message);
        }

        /// <summary>
        /// 重新建立连接之前的错误
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerConnectionRestored (object sender, ConnectionFailedEventArgs e) {
            Console.WriteLine ("ConnectionRestored: " + e.EndPoint);
        }

        /// <summary>
        /// 连接失败 ， 如果重新连接成功你将不会收到这个通知
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerConnectionFailed (object sender, ConnectionFailedEventArgs e) {
            Console.WriteLine ("重新连接：Endpoint failed: " + e.EndPoint + ", " + e.FailureType + (e.Exception == null ? "" : (", " + e.Exception.Message)));
        }

        /// <summary>
        /// 更改集群
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerHashSlotMoved (object sender, HashSlotMovedEventArgs e) {
            Console.WriteLine ("HashSlotMoved:NewEndPoint" + e.NewEndPoint + ", OldEndPoint" + e.OldEndPoint);
        }

        /// <summary>
        /// redis类库错误
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void MuxerInternalError (object sender, InternalErrorEventArgs e) {
            Console.WriteLine ("InternalError:Message" + e.Exception.Message);
        }

        #endregion 事件
    }
}